Antibacterial Efficacy of a Propolis Toothpaste and Mouthrinse Against a Supragingival Multispecies Biofilm

Purpose: To determine in vitro the antibacterial properties of propolis toothpaste and mouthrinse against an in vitro multispecies biofilm model. Materials and Methods: Six-species biofilms grown anaerobically on pellicle-coated hydroxyapatite disks were fed with glucose/sucrose-supplemented medium 3 times daily for 45 min and incubated in 37°C saliva between feedings for up to 64.5 h. At each interval, biofilms were exposed to six different slurries and solutions, including: 1) toothpaste without propolis, 2) toothpaste with propolis, 3) toothpaste with chlorhexidine, 4) mouthrinse with propolis, 5) mouthrinse with chlorhexidine, 6) saline solution (control). Afterwards, biofilms were harvested and the number of colony forming units were determined (CFU). The results were analysed using ANOVA, followed by the Bonferroni test at a 5% significance level. Results: The strongest CFU reduction was shown after treatment with 0.12% chlorhexidine (p 0.0004). When comparing the different toothpastes, there was no statistically significant difference (p 0.05) in CFU reduction. However, they all showed a significant reduction in CFU of more than one log-step vs the saline control group. Nevertheless, the propolis-containing mouthrinse showed no significant reduction in CFU. Conclusion: All toothpastes under investigation displayed some growth inhibition in this supragingival biofilm model, which accounted for an approximately 80%-88% linear reduction. However, the propolis mouthwash had no effect. Keywords: antimicrobial activity, biofilm, dentifrices, propolis, S. mutans